(1) Field of the Invention
This invention relates to a positioning device for bottles having positioning spots. The positioning device is used for a rotary labeling machine, bottle printing machine or the like in which, by setting the positions or directions of bottles reliably and with accuracy, the application of labels or printing to predetermined areas of bottles can be carried out accurately.
(2) Description of the Prior Art
In the positioning device for bottles having positioning spots in the conventional art, the setting of the angular position of a bottle is generally performed by the method such that a roller is pressed to the outer surface of the bottle under spring force, the bottle is rotated by turning the roller and the rotation of the bottle is stopped by bringing the positioning spot on the bottle wall into contact with a stopper which is disposed at a predetermined position.
In the prior art device, however, the above roller must be pressed to the bottle under the force which is sufficient to turn the bottle. At the same time, the roller and the bottle must be allowed to slip after the engagement of the stopper with the positioning spot of the bottle. It is quite difficult to control the contact pressure between the roller and the bottle surface into the most adequate state. Therefor, the slipping of the roller is often caused to occur, which result in a lowering of the accuracy of the positioning or a loss of the positioning function.